Association between calcium/magnesium ratio and insulin resistance in women with obesity and normal-weight women

ABSTRACT The aim of this study was to evaluate the association between the calcium/magnesium (Ca/Mg) ratio and insulin resistance in women with obesity and normal-weight women. This was a cross-sectional study with 128 women (62 women with obesity and 66 normal-weight women). We measured dietary minerals intake and analyzed magnesium and calcium biomarkers. Ca/Mg ratio in diet, plasma and urine were calculated. We have evaluated glycemic parameters. Women with obesity had low dietary magnesium, reduced plasma and erythrocyte magnesium concentrations, and elevated urinary magnesium excretion. Plasma calcium concentration was lower and urinary calcium excretion was higher in patients with obesity than in the normal-weight group. Dietary magnesium and calcium intake per kilogram of body weight per day was lower in obese women than in the control group. Ca/Mg ratio in plasma and urine were elevated in women with obesity. We found a significant correlation among magnesium biomarkers and calcium parameters. Ca/Mg ratio seems to be associated with insulin resistance in obese women.

RESUMEN El objetivo de este estudio fue evaluar la asociación entre la relación Ca/Mg y la resistencia a la insulina en mujeres con obesidad y en mujeres con peso normal. El diseño del estudio fue transversal y participaron 128 mujeres (62 mujeres con obesidad y 66 mujeres con peso normal). Se analizó la ingesta de minerales en la dieta y se realizaron análisis de biomarcadores de magnesio y calcio. Se calculó la relación Ca/Mg en dieta, plasma y orina y se evaluaron los parámetros glicémicos. Las mujeres con obesidad tenían niveles bajos de magnesio en la dieta, concentraciones reducidas de magnesio en plasma y eritrocitos, y excreción urinaria de magnesio elevada. La concentración plasmática de calcio fue menor en pacientes con obesidad, y la excreción urinaria de calcio fue mayor que en el grupo de mujeres con peso normal. La ingesta dietética de magnesio y calcio por kilogramo de peso corporal por día fue menor en las mujeres con obesidad, que en el grupo control. La relación Ca/Mg en plasma y orina estaba elevada en mujeres con obesidad. Se encontró una correlación significativa entre los biomarcadores de magnesio y los parámetros de calcio. La relación Ca / Mg parece estar asociada con la resistencia a la insulina en mujeres con obesidad.

Selenium status and oxidative stress in obese: Influence of adiposity.

BACKGROUND: Selenium deficiency appears to limit antioxidant defense in obese individuals. This study evaluated the association between adiposity indices, selenium status, and oxidative stress in obese women. METHODS: This was a cross-sectional study involving 139 women who were divided into the following two groups: the case group (obese women, n = 63) and the control group (normal-weight women, n = 76). Plasma, erythrocyte, and urinary selenium levels were determined using inductively coupled plasma optical emission spectrometry. Body weight, height, waist circumference, hip circumference and neck circumference were measured. Body mass index, waist/height ratio, conicity index, body fat index, body adiposity index, body circularity index, and visceral adiposity index were calculated. Plasma levels of thiobarbituric acid reactive substances were determined. The erythrocyte glutathione peroxidase activity was determined using an automatic biochemical analyzer and Ransel kit. RESULTS: Obese women had selenium deficiency characterized by reduction in plasma and erythrocyte concentrations (P < .001). The urinary selenium excretion was higher in the case group compared to the control group (P < .001). Adiposity indices values and plasma concentrations of thiobarbituric acid reactive substances were significantly elevated in obese women (P < .001). There was a significant association between adiposity indices and selenium status (P < .001), and between erythrocyte selenium and erythrocyte glutathione peroxidase activity (P < .001). CONCLUSION: Obese women evaluated in the study have reduced plasma and erythrocyte concentrations of selenium and an increased urinary excretion of selenium. The correlation analysis reveals an association between intra-abdominal fat accumulation and selenium metabolism and oxidative stress.

Micronutrient deficiencies in normal and overweight infants in a low socio-economic population in north-east Brazil.

BACKGROUND: Micronutrient deficiencies are the most prevalent form of malnutrition worldwide. Although commonly related to underweight, micronutrient deficiencies can occur in both normal and overweight children in medium- and low-income populations undergoing nutritional transition. OBJECTIVE: To describe haemoglobin and micronutrient levels in infants from a low-income area in Brazil in relation to their weight-for-length Z-score. METHODS: A cross-sectional survey was undertaken of 2-11-month-old infants in Laranjeiras, a small urban community in North-east-Brazil between April 2009 and February 2010. Anthropometry and assays for haemoglobin, ferritin, plasma zinc, copper and selenium and erythrocyte zinc and copper concentrations were investigated. RESULTS: The total number of full-term infants born in the study period was 222, of whom 153 were available for the study. Three (2%) children were wasted, 98 (66%) were of normal weight, 37 (25%) were at risk of overweight and 11 (7%) were overweight or obese. Nearly all (97%) children had at least one micronutrient deficiency, 102 (67%) had anaemia, 86 (58%) and 100 (67%) had plasma and erythrocyte zinc deficiency, respectively, and 7 (5%) and 113 (76%) had plasma and erythrocyte copper deficiency, respectively. 138 (91%) children had selenium deficiency. Except for plasma zinc, the proportion of infants with micronutrient deficiencies did not differ by weight-for-length status. CONCLUSIONS: The increased risk of overweight and micronutrient deficiencies in this population highlights the need to address the double burden of excess weight with micronutrient deficiencies in medium- and low-income settings.